Sociological Heavyweights

This article is excerpted from the current edition of Extraordinary Health magazine. For the rest of this article and more, check out the quarterly issue of Extraordinary Health magazine, available now at local health food stores.

Our friends influence us in all sorts of ways—everything from the brands of clothes we wear to the movies we see to the books we read. But did you know that your friends could influence your weight—in particular your tendency to gain weight? It’s true. And what’s more, they may have the ability to do so whether they live close to you or live hundreds of miles away.

You may be asking yourself, How can this be? Here’s how:
Have you ever “caught” a cold? Chances are that you have. Cold viruses are numerous and are highly contagious especially during the fall and winter months. The word contagious—literally “communicable by contact”—describes an easily transmitted disease such as the common cold or the flu. You “catch” a cold because you’re around someone who’s contagious with a cold virus.

But what about obesity? Is it really possible to “catch” obesity? According to some recent findings, you can—but not in the same way you catch a cold. Apparently, obesity is passed along through “social contagion,” a term used by psychologists to describe the imitative or copycat behavior based on the power of suggestion, word of mouth influence, or, in the case of obesity, relational influence along friendship ties.

The recent findings of a primary study on the topic of obesity indicate the power of our friends’ influence on our weight. A study coauthored by Nicholas Christakis, professor of Medical Sociology at Harvard Medical School and James Fowler, associate professor of Political Science at the University of California in San Diego (published in July 26, 2007 issue of the New England Journal of Medicine) suggests that obesity is “socially contagious,” spreading from person to person in a social network.

The researchers, who studied “networks” of obesity, found that if someone’s friend becomes obese, then that person’s chances of becoming obese increase by more than half—57 percent to be exact. The analysis revealed that the infectious effect is much greater among friends of the same sex; you have a 71 percent increased risk of obesity if your same-sex friend gains a lot of weight. Among mutual friends, the effect is even stronger, with chances increasing by a whopping 171 percent.

Additionally, the researchers found that, on average, having an obese friend made a person gain 17 pounds, which put many people over the body mass index (BMI) measure for obesity.

In addition:

People whose siblings became obese were themselves 40 percent more likely to grow obese. (If you are a woman and your sister becomes obese, your risk rises by 67 percent; however, if a man’s brother becomes obese, his risk rises by 44 percent.)

People whose spouses became obese were 37 percent more likely to become obese, too.

There was no effect among neighbors, unless they were also friends.

Dr. Fowler noted, “We were stunned to find that friends who live hundreds of miles away have just as much impact as friends who are next door.” That is an unbelievable impact—to be able to influence your friend’s weight from hundreds of miles away!

A burning question as a result of this study is this: If friends can influence us to gain weight, can they also influence us to lose weight?

The study’s researchers are not sure, but they propose that this same contagious social influence should be exploited to spread positive health behaviors from one person to that person’s entire social network.

The very nature of social contagion lends itself to positive outcomes as well as negative ones. You’ve heard the adage, “Friends don’t let friends drive drunk.” Well . . . friends don’t let friends get or remain fat, either—especially when they know the damage obesity causes.

So use your friendship networks and influence for good. Start spreading positive health behaviors, beginning with a healthy weight.

This information is intended for educational and informational
purposes only. It should not be used in place of an individual consultation or examination
or replace the advice of your health care professional and should not be relied upon to determine
diagnosis or course of treatment.